The pancreatic islet contains Alfa, beta, gamma and delta cells primarily. Alfa cells give Glucagon, beta cells insulin, gamma cells gastrin and delta cells somatostatin.

An insulinoma is a benign tumor of the pancreas derived from the beta islet cells.

Insulinomas produce excessive amounts of insulin, this causes low blood sugar and unless sugar is given immediately, the patient can potentially go into a coma and die.

Symptoms of insulinoma include:

• Dizziness
• Disorientation
• Weight gain, Patients feel better after they eat so they eat more frequently
• 85% of the patients have blurred vision, palpitations, sweating and weakness as hypoglycaemia produces adrenaline which causes these effects. Must suspect it in a hypoglycemic who is obese or is gaining weight rapidly.
• Seizures ( grand mal seizures)
• Confusion, abnormal behaviour, unconsciousness or amnesia
• Symptoms can be aggravated by exercise, alcohol, hypocaloric diet, and treatment with sulfonylureas

A low fasting blood sugar with high levels of insulin confirms the diagnosis.

High C-peptide levels

Most of these tumors are small and detection of the tumor in the pancreas may be difficult.

Some of the studies that are performed to detect the tumor include a

CT scan

MRI

Octreotide scan

Endoscopic ultrasound.

Medical:

Hydrochlorothiazide to counteract the edema and hyperkalemia secondary to diazoxide.

Octreotide has been used to suppress insulin secretion and effect of the therapy depends on the presence of somatostatin receptor subtype 2 on insulinoma tumor cells.

Glucagon should be available for emergency use.

Surgery is the preferred treatment for insulinoma. The location of the tumor is determined using diagnostic testing or surgical exploration.

Since Insulin can be bought without a prescription, one must suspect exogenous insulin administration. Typically a nurse or paramedic by profession. It can be diagnosed by finding hypoglycemia in a patient but decreased C-peptide levels.

Lots of questions are based on this fact. If a patient takes oral hypoglycemics to cause hypoglycemia, we know that Sulfonylureas increase production of endogenous insulin. The C-peptide in such patients will be high too. Urine test for Sulfonylurea will be positive in cases of factitious Sulfonylurea administration.